Zoned Catalyst For Diesel Applications
AssigneeBASF SE
InventorsM. Shahjahan Kazi, Fabien A. Rioult, Stanley A. Roth, Kenneth E. Voss
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Abstract
An oxidation catalyst composite, methods, and systems for the treatment of exhaust gas emissions from a diesel engine are described. More particularly, an oxidation catalyst composite including a zoned diesel oxidation catalyst with a first washcoat zone with a Pt/Pd ratio that is less than 3:1 and a PGM loading at least twice that of a second washcoat zone.
Claims21
An oxidation catalyst composite for abatement of exhaust gas emissions from a diesel engine comprising:
- a substrate having a length, an inlet end and an outlet end, a catalytic material on the carrier, the catalytic material including a first washcoat zone and a second washcoat zone;
- the first washcoat zone comprising a first washcoat layer including platinum Pt and palladium Pd platinum group metal (PGM) components and a first refractory metal oxide support, the first washcoat zone adjacent the inlet end of the substrate;
- and
- the second washcoat zone comprising a second washcoat layer including platinum and palladium PGM components and a second refractory metal oxide support, the second washcoat layer adjacent the outlet end of the substrate;
- wherein the first washcoat zone has a length that is shorter than the second washcoat zone, wherein the oxidation catalyst does not include an elevated PGM loading on the inlet face of the catalyst and the first washcoat zone has a PGM loading at least twice that of the second washcoat zone, and the first washcoat zone has a Pt/Pd ratio less than 3:1.
A method for treating a diesel exhaust gas stream comprising passing the exhaust gas stream through an inlet end towards an outlet end of a catalyzed soot filter, the exhaust gas first passing through a first washcoat zone on the catalyzed soot filter comprising a first washcoat layer including platinum Pt and palladium Pd components and a first refractory metal oxide support, and then passing the exhaust gas stream through a second washcoat zone on the catalyzed soot filter comprising a second washcoat layer including platinum and palladium components and a second refractory metal oxide support, wherein the first washcoat zone has a length that is shorter than the second washcoat zone, wherein the first washcoat zone has a PGM loading at least twice that of the second washcoat zone, and the first washcoat zone has a Pt/Pd ratio less than 3:1.
Dependencies are inferred from the claim text.